\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{matrix,chains,positioning,decorations.pathreplacing,arrows}

\usepackage[margin=0in]{geometry}

\begin{document}

\begin{tikzpicture}[
plain/.style={
  draw=none,
  fill=none,
  },
net/.style={
  matrix of nodes,
  nodes={
    draw,
    circle,
    inner sep=10pt
    },
  nodes in empty cells,
  column sep=2cm,
  row sep=-9pt
  },
>=latex
]
\matrix[net] (mat)
{
|[plain]| \parbox{1.3cm}{\centering Capa de\\entrada} & |[plain]| \parbox{1.3cm}{\centering Capa\\oculta} & |[plain]| \parbox{1.3cm}{\centering Capa de\\salida} \\
& |[plain]| & |[plain]| \\
|[plain]| & & |[plain]|  \\
& |[plain]| & |[plain]| \\
|[plain]| & & |[plain]|  \\
& |[plain]| & |[plain]| \\
|[plain]| & |[plain]| & |[plain]|  \\
|[plain]| & |[plain]| & \\
|[plain]| & |[plain]| & |[plain]|  \\
& |[plain]| & |[plain]| \\
|[plain]| & & |[plain]|  \\
& |[plain]| & |[plain]| \\
|[plain]| & & |[plain]|  \\
& |[plain]| & |[plain]| \\
};

\draw[<-] (mat-2-1) -- node[above] {X(1)} +(-2cm,0);
\draw[<-] (mat-4-1) -- node[above] {X(2)} +(-2cm,0);
\draw[<-] (mat-6-1) -- node[above] {X(3)} +(-2cm,0);
\draw[<-] (mat-8-1) -- node[above] {...} +(-2cm,0);
\draw[<-] (mat-10-1) -- node[above] {X(n-2)} +(-2cm,0);
\draw[<-] (mat-12-1) -- node[above] {X(n-1)} +(-2cm,0);
\draw[<-] (mat-14-1) -- node[above] {X(n)} +(-2cm,0);

\draw[->] (mat-8-3) -- node[above] {Y} +(2cm,0);
\draw[->] (mat-8-2) -- node[above] {...} +(1,0);


\foreach \ai [count=\mi ]in {2,4,6,10,12,14}
{	\foreach \aii in {3,5,11,13}
  	\draw[->] (mat-\ai-1) -- (mat-\aii-2);
}

\foreach \ai [count=\mi ]in {3,5,11,13}
  	\draw[->] (mat-\ai-2) -- (mat-8-3);

%\foreach \ai [count=\mi ]in {2,4,8,10}
%{	\foreach \aii in {2,4,8,10}
%  	\draw[->] (mat-\ai-2) -- (mat-\aii-3);
%}

%\foreach \ai [count=\mi ]in {2,4,...,10}
%  \draw[<-] (mat-\ai-1) -- node[above] {X(\mi)} +(-2cm,0);
%\foreach \ai in {2,4,...,10}
%{\foreach \aii in {3,6,9}
%  \draw[->] (mat-\ai-1) -- (mat-\aii-2);
%}
%\foreach \ai in {3,6,9}
%  \draw[->] (mat-\ai-2) -- (mat-6-3);
%\draw[->] (mat-6-3) -- node[above] {Y(\ai)} +(2cm,0);
\end{tikzpicture}

\end{document}